The present invention relates to a technique for producing an absorbent article. More particularly, the invention relates to a method and apparatus for forming an absorbent article having a first superabsorbent-containing stratum, and at least a second superabsorbent-containing stratum.
Absorbent articles and structures, such as absorbent pads and absorbent cores, have been formed by employing various techniques, such as wet forming techniques, and air laying techniques. Conventional air laying techniques have transported a foraminous forming surface, such as a forming screen, through a forming chamber. Fibrous materials and particulate materials have been introduced into the forming chamber, and a vacuum source has been employed to draw an air stream through the forming surface. The air stream entrains the fibers and particulate material for deposition onto the moving forming surface.
Multiple forming chambers have been employed to form different layers of material in a composite absorbent article. The different layers can be composed of different types of fibrous material, and different types of particulate material.
Such conventional techniques, however, have been excessively complex and costly. In addition, such conventional techniques have not adequately provided the desired superabsorbent-containing strata within a selected absorbent article. As a result, there has been a continued need for improved techniques for generating distinctive superabsorbent-containing strata within a composite absorbent article.
The present invention provides a method and apparatus for forming a plurality of strata which include a superabsorbent material and a fibrous matrix. The technique of the invention can include a moving of a forming surface in a forming chamber. A first fibrous stratum of fiber material can be deposited to overlie the forming surface, and the first fibrous stratum can have a first stratum thickness. In a particular aspect, a first quantity of superabsorbent material can be directed to form a first superabsorbent-containing region which is in a selected combination with the first fibrous stratum. Another aspect can include a depositing of a second fibrous stratum of fiber material to overlie the first fibrous stratum, and the second fibrous stratum can have a second stratum thickness. In a further aspect, a second quantity of superabsorbent material can be directed to form a second superabsorbent-containing region which is in a selected combination with the second fibrous stratum.
Yet another aspect of the invention, can provide a technique which includes a moving of a forming surface in a forming chamber along a forming path length. A first fibrous stratum of fiber material can be deposited to overlie the forming surface, and the first fibrous stratum can have a first stratum thickness. A first quantity of a first superabsorbent material can be directed with a first nozzle to form a first superabsorbent-rich stratum within the first stratum thickness, and the first nozzle can be oriented at a first nozzle angle relative to a first local section of the forming surface. In a further aspect, a second fibrous stratum of fiber material can be deposited to overlie the first fibrous stratum, and the second fibrous stratum can have a second stratum thickness. Additionally, a second quantity of a second superabsorbent material can be directed with a second nozzle to form a second superabsorbent-rich stratum within the second stratum thickness, and the second nozzle can be oriented at a second nozzle angle relative to a second local section of the forming surface.
In its various aspects and configurations, the present invention can advantageously provide an effective and cost efficient technique for forming a plurality of selected strata of superabsorbent and fibrous material within an absorbent article. The technique of the invention can avoid the need for multiple forming chambers, and can be configured to more effectively provide a predetermined distribution of superabsorbent material and fibrous material within each of the selected strata of the absorbent article. As a result, the method and apparatus of the invention can produce an absorbent article having improved absorbent performance, and can produce an article having an improved combination of liquid uptake, liquid distribution, absorbent capacity, and leakage resistance.